It seems like the question you're posing is: in the context of colon cancer risk, if one's alcohol consumption isn't enough to reach the category of "moderate", does that mean the increased risk is zero (or insignificant)? I don't know the answer to that. That's something that could perhaps be determined by reviewing the literature.
Edit: Not that anyone cares, but I guess I'll say a bit more: I don't know what brand of kombucha OP drinks, or how much of it, and how many grams of alcohol that sums up to, and what the current body of research says (or doesn't) regarding the precise amount of risk incurred or not from that amount of alcohol ... but the fact is, there's extensive research on the association between alcohol and cancer and I stand by the suggestions that someone dealing with recurrent colon cancer should be cautious about alcohol consumption, and that it could be worth reviewing existing research on the matter.
Edit: Not that anyone cares, but I guess I'll say a bit more: I don't know what brand of kombucha OP drinks, or how much of it, and how many grams of alcohol that sums up to, and what the current body of research says (or doesn't) regarding the precise amount of risk incurred or not from that amount of alcohol ... but the fact is, there's extensive research on the association between alcohol and cancer and I stand by the suggestions that someone dealing with recurrent colon cancer should be cautious about alcohol consumption, and that it could be worth reviewing existing research on the matter.